import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

import org.korifey.ffalg.NumberTheory;
import org.korifey.ffalg.Probabilities;


public class Problem20 {
	
	public static void main(String[] args) {
		System.out.println(solve());
	}
	static int n = 100;
		
	public static long solve() {
		BigInteger x = BigInteger.ONE;
		for (int i=2; i<=n; i++) {
			x = x.multiply(BigInteger.valueOf(i));
		}
		
		int res = 0;
		for (char c: x.toString().toCharArray()) {
			res += c-'0';
		}
		return res;
	}
	
}
